Information Technology Reference
In-Depth Information
On the other hand one can have a digital object for which it is not enough to
simply render it but for which one needs to know what the contents mean in order
to be able to further process it.
It is useful to make this distinction because it is easy to think that every digital
object is simply rendered; that every digital object need only be displayed.
Indeed one could argue that the ultimate user of a digital object is a
human who needs to see or hear (or perhaps in future to feel, taste or
smell) the result. For example even a FITS image is (often) displayed.
However displaying a FITS image is rarely the ultimate aim. Instead
an astronomer might want to make measurements which require an
understanding of the units and coordinate systems. He/she might also
reasonably want to combine this piece of data with another. In other
words what is wanted is to do more than render it in one particular
way; instead there is an enormous variety of ways users may want to
deal with the object.
When we are thinking about digital preservation one must look to
the future - not in order to guess what it may to be but rather to
recognise that it may be different from today. Therefore we need
to identify what someone - at least the Designated Community -
needs in order to understand and use a non-rendered object digital
object in any number of different ways.
For example consider two text files. In one case one can have some English text,
say a recipe for a cake in a file “recipe.txt” (see Fig.
4.4
). Using a Windows PC
the file is easily readable because the “.txt” part of the name lets the machine try
an application which can display an ASCII encoded file - which is what this is.
Normally one would say that no special knowledge is needed to understand this - it
simply needs to be read.
However there is a requirement to be able to read English and also to know what
the various measures are (for example what size is “a cup”?) and also to know
what the ingredients are (for example what is “lemon zest”?); without such
knowledge the recipe is neither understandable nor usable.
Take 2 eggs
Add 3 cups of gram flour
Add 2 tsp lemon zest
......
Fig. 4.4
Text file “recipe.txt”
